268 Mr. O. Thomas on Gerbils 
Dimensions of the type :— 
Head and body 142 mm.; tail 153; hind foot 34; 
ear 20. 
Skull: median Jeneth 40°5; diagonal length 42; zygo- 
matic breadth 22; interorbital breadth 7°6; bimeatal breadth 
23; palatine foramina 8 2; upper molar series 5°3. Bulle: 
diagonal horizontal leneth 17°5; front of meatal swelling 
to back of bulla 15:1; suprameatal triangle, length 4:5, 
height 3°2. 
Hab. Tripoli. Type from Ferdjan, a second specimen 
from El Hammam. 
Type. Adu't male. B.M. no. 2.11. 4.56. Original 
number 97. Collected 21st June, 1901, by KE. Dodson. 
Presented by J. J. S. Whitaker, Esq. 
This is a long-tailed form of the & group, with largest- 
sized bullae but small suprameatal triangle. It occurs 
between the original libycus of Lower Egypt and schousbuer 
of Algeria, which have both comparatively short tails, and 
are, indeed, very doubtfully distinguishable from each other. 
Meriones syrius, sp. 0. 
Nearly allied to WZ. erythrourus, but with longer foot and 
larger teeth. 
General characters quite as in erythrourus, with the same 
proportions of the bulla and approximately the same colora- 
tion of body and tail. Upper surface near ‘ pinkish buff,” 
paler and more approaching “ light buff”? on sides. Under 
surface white, but the hairs pale slaty basally except en the 
chin and throat, where they are white to the roots. Light 
areas behind eyes and round bases of ears not strongly 
marked, ars like head, the fiinging hairs buffy white. 
Hands and feet white, more or less washed with buffy on the 
metapodials, Tail ochraceous, the terminal crest well deve- 
loped, black, commencing rather more than halfway along 
the upper side. 
Skull apparently like that of erythrourus, though rather 
more robustly built. Bulle equally large, with a marked 
inflation on the front side of the meatus just surpassing the 
level of the hindermost point of the zygoma. 
Incisors less bevelled and with less sharply defined groove 
than in erythrourus. Molars distinctly smaller. 
Dimensions of the type :— 
Ilead and body 142 mm.; tail 145; hind foot 35; 
ear 18. 
Skull: median length 42°5; diagonal length to back of 
